A&P Test 3

  1. The basic building block of the nervous system.
    Neuron
  2. The cell body of the neuron.
    Soma
  3. to be stimulated by other neurons or by special receptor cells (such as hair cells in the cochlea or vestibular system)
    Dendrites basic function
  4. Act as receiving ends of the nerve cells
    Convey nerve impulses into the cell body
    Dendrites (2)
  5. Long and thin extensions of the cell body; convey information away from the cell body
    Axon
  6. The point at which a nerve impulse is passed from the axons of one nerve cell to the dendrites of another nerve cell; the junction of two neurons
    Synapse
  7. A thin white sheath of fatty substances that surrounds the axons of most fibers; acts as an insulator between the positively charged axon and the negatively charged surrounding environment
    Myelin sheath
  8. made up of the brain and spinal cord
    Central Nervous System (CNS)
  9. a collection of nerve cells bodies in the CNS
    Nucleus
  10. Collection of nerve cell bodies that have a common function but lie outside the CNS
    Ganglion
  11. Cell bodies of the neurons that innervate the hair cells of the cochlea
    Spiral ganglion of Corti definition
  12. Found in the modiolus
    Spirals with the turns of the cochlea
    Spiral ganglion of Corti (2)
  13. Small openings in the edge of the osseous spiral lamina
    Habenula Perforata
  14. Neurons carry information in one direction; that is, they are unidirectional
    Cochlear Innervation
  15. There are 30,000 or more auditory nerve fibers in humans. ____ of the fibers go to the OHC. At least ____of the fibers go to the IHC.
    There are ______ in humans. 10% or fewer of the fibers go to the OHC. At least 90% of the fibers go to the IHC.
  16. carry information from the hair cells to the brain.
    Afferent nerve fibers
  17. Afferent nerve fibers originating from the IHC
    Radial Fibers definition
  18. compose 95% of the afferent fibers
    Primary carriers of sensory information
    Any one afferent neuron supplies but one IHC, but any single hair cell is supplied by 8-10 neurons
    Radial fibers
  19. Afferent fibers connected to the OHC
    Outer Spiral Fibers definition
  20. compose 5% of the afferent fibers
    One neuron receives input from many OHCs; or, said another way, many OHCs share one neuron
    Outer spiral fibers
  21. carry information from the brain to the hair cells
    Efferent nerve fibers
  22. Efferent fibers connected to the OHC
    Tunnel Radial Fibers definition
  23. Controls cochlear amplifier
    Innervation is denser at the base of the cochlea
    Tunnel Radial Fibers (2)
  24. Efferent fibers that connect to the IHC
    Inner Spiral Fibers: Inhibition of afferent fibers
  25. Arranged with respect to frequency
    Tonotopic organization
  26. Neurons carrying _______ information located on the outside of auditory nerve; neurons carrying ________ information are located in the center
    Neurons carrying high frequency information located on the __________; neurons carrying low frequency information are located ______.
  27. Central Auditory Pathway
    • Brainstem
    • Diencephalon
    • Cortex
  28. _________
    The medulla, which is continuous with the spiral ganglia
    The pons, which is above the medulla
    The midbrain, which is above the pons
    Brainstem
  29. ____________
    Located above the midbrain and is surrounded by the cerebral hemisphere
    Contains the Thalamus
    Diencephalon
  30. ________
    Is made up of two cerebral hemispheres
    Each hemisphere contains four lobes: Frontal, Parietal, Occipital, Temporal
    Cortex
  31. 1st Order: Auditory Nerve to Cochlear nucleus
    • VIII cranial nerve contains both auditory and vestibular fibers.
    • Travels from the cochlea to the brainstem via the internal auditory meatus
    • Joins the brainstem at the cerebellopontine angle
    • Fibers then travel ipsilaterally to the Cochlear Nucleus located in the medulla where they synapseNerve TrunkNerve bundleNeuron with myelin sheath
  32. 2nd Order: CN to Superior Olivary Complex
    • Approx. 2/3rds of the fibers decussate after leaving the CN and travel to the SOC on the contralateral side where they synapse
    • The remaining 1/3rd of the fibers ascend to the SOC on the ipsilateral side where they synapse
    • Binaural information is first available at the SOC, which is important for localization
    • The SOC is also located in the medulla
  33. 3rd Order: SOC to Nucleus of the Lateral Lemniscus
    • The fibers ascend ipsilaterally and contralaterally from the SOC to the NLL where they synapse
    • NLL is located in the pons
  34. 4th Order: NLL to Inferior Colliculus
    • The fibers ascend ipsilaterally and contralaterally from the NLL to the IC where they synapse
    • The two inferior colliculi are connected by fibers allowing a crossover of information from one side of the brainstem to the other
    • The IC is located in the midbrain
  35. 5th Order: IC to Medial Geniculate
    • The fibers ascend ipsilaterally from the IC to the Medial Geniculate, where they synapse
    • The MG is located in the Thalamus
  36. 6th Order: MG to Cortex
    The fibers ascend ipsilaterally to the auditory cortex in the temporal lobe, at the anterior transverse temporal gyrus (Herschel’s gyrus), where they synapse
  37. Descending Auditory Pathway: Efferent fibers
    • Essentially same structures as afferent pathways, but in reverse order
    • Outer hair cells more often the destination
  38. From the SOC upward, ______ contain information from both ears
    First point where hearing from both ears is represented is___.
    The SOC is responsible for the ability to______.
    _______ is present at each nucleus
    • _________ , both ipsi and contra tracts contain information from both ears
    • First point where hearing from both ears is represented is the SOC
    • The SOC is responsible for the ability to localize sounds in space
    • Tonotopic organization is present_____.
  39. Peripheral Nervous System
    • Cranial Nerves
    • Spinal Nerves
  40. Cranial Nerves
    • Twelve pairs identified by a roman numeral and a name, ordered from top to bottom of the brainstem.
    • Name may reflect function, structure, or distribution
    • Nerve is an aggregate of neuron fibers
    • Nerves may be afferent or efferent; most are both
  41. Twelve Cranial Nerves
    Which are important for speech?
    • Trigeminal
    • Facial
    • Glossopharyngeal
    • Vagus
    • Accessory
    • Hypoglossal
  42. V. Trigeminal Nerve
    • Largest cranial nerve
    • Sensory portion (afferent)
    • face
    • mouth
    • lower jaw
    • Motor portion (efferent)
    • muscles of mastication
    • velum
    • mylohyoid and anterior belly of digastric
  43. VII. Facial
    • Large and complex
    • Facial nerve proper--efferent
    • Nervous intermedius--both efferent and afferent
    • Communicates w/ other cranial nerves
    • Trigeminal
    • Vagus
    • Glossopharyngeal
    • Cervical
    • Muscles of facial expression, from above the eye to lower jaw
  44. IX. Glossopharyngeal
    • Both sensory and motor
    • Supplies the tongue and pharynx
  45. X. Vagus
    • “Wandering Course”: large distribution of nerves
    • Both afferent and efferent courses
    • Serves large array of structures:
    • Larynx
    • Pericardium
    • Stomach
    • Pancreas
    • Spleen
    • Kidneys
    • Intestines
    • Liver
  46. XI. Accessory
    • Partly cranial and partly spinal
    • Interacts with vagus nerve
    • Serves: Larynx, Sternocleidomastoid, Trapezius muscles
  47. XII. Hypoglossal
    • Primarily motor
    • Supplies: Intrinsic tongue muscle
    • Extrinsic tongue muscles
    • Strap muscles
Author
amykath
ID
151583
Card Set
A&P Test 3
Description
Speech and Hearing Anatomy, SLP
Updated